pw_toolchain_bazel/constraints/arm_mcpu/BUILD.bazel

# Copyright 2023 The Pigweed Authors
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may not
# use this file except in compliance with the License. You may obtain a copy of
# the License at
#
#     https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations under
# the License.

package(default_visibility = ["//visibility:public"])

licenses(["notice"])

# The target Arm processor.
#
# The values of this constraint_setting correspond to valid values of the -mcpu
# flag for Arm gcc. See
# https://gcc.gnu.org/onlinedocs/gcc/ARM-Options.html#index-mcpu-2. These
# values are intended to be used in `target_compatible_with` attributes of
# toolchains which specify the corresponding value of -mcpu.
#
# The constraint_values are not currently exhaustively enumerated (only a few
# of the legal -mcpu values have corresponding constraint_values). The intent
# is for additional values to be added when needed.
#
# The intent is to support only (processor type + optional architectural
# extensions) forms of -mcpu (e.g., cortex-m4 or cortex-m4+nofp), not march
# values (e.g., armv7e-m). This is because it is recommended to use (processor
# type + optional architectural extensions) when configuring Arm GCC (see
# https://community.arm.com/arm-community-blogs/b/tools-software-ides-blog/posts/compiler-flags-across-architectures-march-mtune-and-mcpu).
# In addition, the march values can already be captured using @platforms//cpu.
constraint_setting(
    name = "mcpu",
    default_constraint_value = "none",
)

constraint_value(
    name = "none",
    constraint_setting = ":mcpu",
)

constraint_value(
    name = "cortex-m0",
    constraint_setting = ":mcpu",
)

constraint_value(
    name = "cortex-m3",
    constraint_setting = ":mcpu",
)

constraint_value(
    name = "cortex-m4",
    constraint_setting = ":mcpu",
)

constraint_value(
    name = "cortex-m4+nofp",
    constraint_setting = ":mcpu",
)

constraint_value(
    name = "cortex-m7",
    constraint_setting = ":mcpu",
)

constraint_value(
    name = "cortex-m33",
    constraint_setting = ":mcpu",
)

constraint_value(
    name = "cortex-m33+nofp",
    constraint_setting = ":mcpu",
)